Why does red wine typically contain higher quantities of beneficial compounds like resveratrol?

Longer contact time between the grape skins and the juice during fermentation.

The primary reason red wine is often cited as having superior antioxidant power, particularly concerning compounds like resveratrol, is rooted in its production method compared to white or sparkling wines made from similar grapes. During the fermentation process for red wine, the grape skins remain in contact with the juice for an extended period. This prolonged contact allows for a greater extraction of beneficial phenolic compounds present in the skins into the final beverage, resulting in a higher concentration of antioxidants compared to wines where the juice separates from the skins much earlier.